Microstrip Monopole Antenna With Enhanced Bandwidth Using Defected Ground Structure

In this letter, a double U-shaped defected ground structure (DGS) is proposed to broaden impedance bandwidth of a microstrip-fed monopole antenna. The antenna structure consists of a simple trapezoid monopole with a DGS microstrip feedline for excitation and impedance bandwidth broadening. Measurement shows that the antenna has 10-dB return loss from 790 to 2060 MHz, yielding 112.4% impedance bandwidth improvement over that of traditional design.